This invention relates to improvements in an apparatus for predicting a load in the car of an elevator.
In a group-supervisory elevator system, when a hall call has been registered, a car most suited to respond to the hall call is selected on the basis of information required for the group supervision, and the hall call is assigned to this car. In assigning the hall call, it is necessary to consider that the car will not pass any floor due to the full capacity of passengers. To this end, how a load in the car changes must be predicted during the operation of the elevator system.
There has been proposed a measure wherein the calculation of the predicted load in the car is performed in accordance with the destination floor percentages of waiting passengers. The percentages of the waiting passengers of respective halls and in respective directions are evaluated for frontward floors (i.e. floors located frontwards in the running direction of the car with respect to the particular floor where the car lies) in advance, and the predicted number of passengers get on the car by hall calls on the respective halls and in the respective directions and are distributed in accordance with the destination percentages concerning the frontward floors; the predicted number of passengers are subtracted in conformity with the distribution proportions at the frontward floors, whereby the predicted loads in the car at the respective floors are calculated. This will be described with reference to FIGS. 1 to 3 used for explaining the prior-art system for predicting the load in the car of an elevator.
In FIG. 1, numerals 1 to 8 indicate first to eighth floors, respectively. Symbols 4a and 6a denote the up calls of the fourth and sixth floors assigned to a car 9, respectively, while symbol 7b denotes the down call of the seventh floor. FIG. 2 shows a table 10 of destination floor percentages (for up scanning), and FIG. 3 a table 11 of destination distribution (for up scanning).
It is now assumed that the car 9 be ascending at the second floor 2 and respond to the up calls 4a, 6a of the fourth and six floors. The number of people who get on the car at the fourth floor 4 [or an in-car load factor (the percentages of getting-on passengers with respect to the capacity of the car)] is predicted from past data to be equal to three. Then, the number of persons in the car 9 is predicted to be three at the fourth floor 4. Next, the three people at the fourth floor are distributed to the frontward floors by multiplying the number of people by the percentages of the column of the getting-on floor 4 in the destination floor percentage table 10, the percentages being based on data outputted from a statistics unit (not shown). The results become as indicated in the column of the getting-on floor 4 in the destination distribution table 11. Likewise, when the number of people who get on the car at the sixth floor 6 is predicted to be two, the distributed numbers of people become as indicated in the column of the getting-on floor 6 in the destination distribution table 11. The calculated results are stored in a predetermined memory. At the fifth floor, 3-0.6=2.4 (persons) remain in the car. (2.4-0.45)+2=3.95 (persons) remain at the sixth floor 6 because two persons get in here. The number of persons in the car is similarly predictively calculated to be (3.95-0.9)-1=2.05 (persons) at the seventh floor 7, and (2.05-1.05)-1=0 at the eighth floor 8.
With the above prediction apparatus, however, the data of the frontward floor destination percentages are required for the respective floors and for the respective directions, and the predictive loads need to be calculated on all the frontward floors for the respective floors and the respective directions, so that the period of time for the calculations inevitably becomes long. More specifically, although only the destination percentages of the eight floors in the up direction are listed in FIG. 2, actually the destination percentages thereof in the down direction are also necessary. When the apparatus is applied to a many-storied building having a still larger number of floors, more destination percentages are required accordingly. Therefore, a memory of large capacity is required. On the other hand, in predictively calculating the loads in the car, all the distributed numbers of people are computed for the respective floors as indicated in FIG. 3. That is, the predictive calculations are possible for the first time after the results (values 0, 0.6, 0.45, . . . etc. listed in FIG. 3) have been obtained. Therefore, the calculating period of time becomes long. In consequence, the determinations of the cars are made while calls having developed during the calculating operation are neglected, and a car assignment conforming to the real situation might not be performed.